Chain grate



Jan. 17, 1928,

W. M. DUNCAN l656179 CHAIN GRATE .Filed July 14, 1924 2 sheets-sheet 1 mus/v r02 b WM. Dun/can 63/ P Arms.

Jan. 17, 1928.

W. M. DUNCAN CHAIN GRATE Filed July 14, 1924 2 Sheets-Sheet 2 Patented Jan, 17, 1928.'

WILLIAM. u. was, or ALTON, rumors.

cum

Application filed m 14,

This invention relatesto improvementsin chain grates, and more particularly to the structure within and adjacent to the side margin of a traveling chain grate. One of theobjects of the invention is to revent excessive leakage of draft at the 'si e margins of a chain grate. Another object is to produce a chain grate having a novel link structure at its side margins. A further object is to provide achain grate wherein different draft pressures can be efiectively maintained indifferent portions of the grate.

lVith the foregoing and other objects in view, the invention comprises the novel construction, combination and arrangement of parts hereinafter more specifically described and illustrated intheaccompanymg drawings, wherein is shown the preferred embodiment of the invention. However, it is to be understood that the invention comprehends changes, variations and modifications which come within the scope of the claims hereunto appended. y Fig. I is a longitudinal section illustrating a-mechanical stoker embodying the features ofthis invention. I

Fig. II is a transverse section taken approximately onthe line II-II inFig I.

Fig. III is a fragmentary top view illustrating a portion of one side of thestoker, some of the parts being broken away to more clearly show the double side links and the bafile obstructing the draft which tends to how lengthwise of the grate.

Fig. IV is an enlarged vertical section showing the channel at one side of the grate and the baffle in said channel;

Fig. V is ajdetail view showing one of the side links and the pivot rods therein.

A designates an endlesstraveling' chain grate arranged between the side walls 1 of a furnace andsupp'orted partly bybars 2 and 2", located immediately below the fuel-supporting portion of the grate, and partly by bars 3 on which the lower portion of the grate travels. Additional supports are fdrmcd by a roll 4: at the rearof the grate and a suitable number of sprocket wheels 5 secured to an operating shaft 6 at the'front of thegrate Theshaft 6 may be operated .in anysuitable manner to cause the grateto travel in the'direction indicated by arrows I in Fig. I: The fuel is supplied to a hopper PATENT OFFICE,

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1924. semi in. 725,841.

7 at the frontof the grate and the ashes are discharged by gravity at the rear of the grate. v i

The traveling grate is interposed between side frames 8, the latterbeing connected together by means of transverse beams 9 which support the bars Qand 2. Toprovide different draft 'zones the structure preferably includes a series of draft boxes B surrounded by the grate and arranged transversely thereof, each draft box being open at the topfor the discharge of draft through the fuel-supporting portion of the grate. These draft boxes may be constructed in any suitable manner, and in the structure shown the are formed partly by the beams 9 and part y by curved plates 10 connecting the beams. A forced draftmay be supplied through a passageway 11 (Fig. II) formed at the bottom of one of the furnace walls. Each draft box has an inlet opening 12 adapted to commu nicate with the passageway 11. The draft should be regulated to provide different pressures in the severaldraft boxes, and this can be accomplished by controlling the delivery of draft through the several inlets 12. Each inlet is provided with a closure 13 secured to an operating rod 14, slidabl mounted in a bar 15 and extending throng the passageway 11,as shown in Fig. II.

The longitudinal bars 2 and 2 separate the chain grate from the beams 9, and to prevent leakageof draft across the top faces "of said beams transverse bars 16 are preferably mounted on the top faces of the In a mechanical stoker of this t pe it has been difficult to prevent excessive eakage of draft from one zone to another, and the grate.

Top closure bars 17 are adj ustably secured to the side fran'ies 8- by means of bolts 18 passing through slots in said bars, and these bars can be adjusted to extend across the spaces between the grate and the side frames 8. The sides of the grate are preferably lapped. by the bars 17. The side margins of the traveling grate rest upon thelower bars 2 which contact with the respective side frames 8 to form lower closures for the spaces between the side frames and the fuelsupporting portion of the grate. The upper and lower bars 17 and 2 are thus combined with the sideframes 8 to form longitudinal channels at the sides of thegrate, and although three sides of each channel are effectively closed, the other side is open to receive the draft flowing horizontally through the spaces between the ends of adjacent links.

I will now describe a means for baflling the draft in the channels just referred to, thereby preventing free escape of draft at the ends of the channels and also preventing free delivery of draft from one zone to another. Bafiies C, preferably made of yieldable sheet metal, extend across these channels. Each bafile comprises end portions 19 (Figs. III and IV) secured to one of the side frames by means of bolts 20, and a middle portion adapted to contact with the adjacent side face of the traveling grate. Instead of being rigidly secured, each bafile is, slotted, as shown in Fig. III, to receive one of the bolts 20, so the flat middle portion of the baffle is permitted to yield when engaged by an irregular portion of the grate. In addition to extending across the channel in which it is mounted, each baflle preferably extends approximately from the top to the bottom of the channel. The several baflles can be arranged at suitable points in the channels, as shown by Figs. I and III, to prevent free escape of draft from the ends of the channel, and'also to prevent free delivery of draft from one draft zone to another.

The chain grate comprises endless rows of grate links connected by transverse pivot rods'21, and in the ordinary grate of this kind the pivot rods project from the sides of the grate to receive cotter pins'or other retaining devices. However, if the pivot rods were extended from the grate herein shown, they would either strike the baffles (l or permit free leakage of draft past said baffles. Attention is therefore directed to the double links at the sides of the grate and to the manner in which the ends of the pivot rods are arranged to provide substantially smooth surfaces at the sides of the grate.

The double links are shown most clearly by Figs. III, IV and V. The outer link 22 of each pair is united to an inner link 23 in any suitable manner. In the structure shown, the link 23 is provided with spacers 24, and rivets 25 are applied through the spacers to connect the companion links. The pivot rods 21 extend entirely through each inner link 23 and terminate in elongated apertures 26 in the outer link, the latter having webs 27 forming abutments adapted to engage the ends of the pivot rods. Retaining members, such as cotter pins 28, are

secured to the pivot rods arranged within the double links to prevent longitudinal dislacement of said rods. Each cotter pin lies between two of the links 22 and 23, and the elongated apertures 26 are large enough to permit inspection of the cotter pins and to receive a tool for removing the same.

The double links travel on the closure bars 2 which extend under the side margins of the fuel-supporting ortion of the grate. The links in the end ess rows between the margins of the grate are staggered, or lapped, in the usual manner, as indicated in Fig. III, and connected bythe pivot rods to form the endless chain structure, but the double links at the margins are not connected in the same manner. The two links in each pair are not staggered relative to each other, the ends of the two companion links being flush with each other. However, each double link is secured to two of the pivot rods, and the several rods are connected together by the links between the margins of the grate.

I claim:

1. A mechanical stoker comprising side members, an endless traveling chain grate between said side members, means for transmitting draft through the upper portion of said grate, said side members being provided with channels at the sides of the upper portion of the traveling grate, and baflles forming transverse barriers across the entire space between said channels and grate to obstruct the draft tending to flow therethrough.

2. A mechanical stoker comprising side members, an endless traveling chain grate arranged between and separated from said side members, means for transmitting draft through the upper portion of said grate, top closure bars extending from said side members and lapping the upper margin of the traveling grate, lower closure bars extending from said side members and lapping said grate, said lower closure bars being entirely below the upper flight of said endless chain grate and constituting the support therefor, said closure bars and side members forming longitudinal channels at the side margins of the grate, and baflies forming transverse barriers across the entire space between said channels and grate to obstruct the draft tending to flow therethroughr 3. A mechanical stoker comprising side members,

side members, means for transmitting draft through the upper portion of the grate, top closure bars extending from said side members and lapping said traveling grate, lower closure bars extending from said side members and lapping said traveling grate, and bafiles forming transverse barriers across the entire space between said upper and Inn an endless traveling chain grate arranged between and separated from said mentioned side member and provided with a yieldable portion adapted to be engaged by said traveling chain grate.

5. A mechanical stoker comprising side members, an endless traveling chain grate arranged between and separated from said side members, means for transmitting draft through the upper portion of said grate, top closure bars extending from said side members and lapping the upper margin of the traveling grate, lower closure bars extending from said side members and lapping said grate, said closure bars and side members forming longitudinal channels at the side margins of the grate, and battles forming transverse barriers extending entirely across said channels to obstruct'the draft tending to flow along the side faces of the grate, said baffles being connected to the respective side members and provided with yieldable portions adapted to be engaged by the sides of the traveling grate.

6. A mechanical stoker comprising side members, an endless traveling chain grate interposed between and separated from said side members, draft boxeszarranged immediately below the upper portion of the grate to provide different draft zones, said draft boxes being open at the top to discharge draft through the upper portion of said chain grate, and baffles forming transverse barriers entirely across the spaces between the sides of the grate and said side members to obstruct the draft tending to flow from one of said zones to another, said bafiles being connected to the respective side members and provided with yieldable portions adapted to be engaged by the sides of the traveling chain grate.

7 In a mechanical stoker, side members and an endless traveling grate between said side members, said grate comprising endless rows of grate links and pivot rods connecting the same, the links at the sides of the grate being arranged in pairs and the links in each pair being united to form a rigid double link, and the ends of the pivot rods being entirely within the double links.

8. In a mechanical stoker, side members and an endless traveling grate between said side members, said grate comprising endless rows of grate links and pivot rods connecting the same, the links at the sides of the grate being arranged in pairs and the links in each pairbeing united to form a rigid double link, andeach double link being provided with an abutment adapted to engage the end of one of the pivot rods.

9. In a mechanical stoker, side members and an endless traveling grate between said side members, said grate comprising endless rows of grate links and pivot rods connecting the same, the links at the sides of the grate being arranged in pairs and the links in each pair being united to form a rigid double link, and retaining members secured to the pivot rods and arranged within the double links to prevent displacement of the pivot rods, the outer link of each pair being provided with an aperture for inspection and removal of the retaining member associated therewith.

10. In a mechanical stoker, side members and an endless traveling grate between said side members, said grate comprising endless rows of'grate links and pivot rods connect ing the same, the links at the sides of the grate being arranged in pairs and the links in each pair being united to form a rigid double link, the ends of the pivot rods being within the double links, retaining members secured to the pivot rods and arranged within the double links to prevent longitudinal displacement of the pivot rods, and baflles cooperatin with the outer sides of said double lin s to obstruct draft tending to flow along the sides of the grate.

In testimony that I claim the foregoing I hereunto aflix my signature.

WILLIAM M. DUNCAII. 

